Cephalosporins having a ureido acyl side chain are disclosed in U.S. Pat. Nos. 3,673,183; 3,708,479, 3,833,568 and 3,860,591. Cephalosporins having various acyl side chains and a 7.alpha.-methoxy substituent are taught in various U.S. patents including U.S. Pat. Nos. 3,775,410; 3,780,031; 3,780,033; 3,780,034, 3,780,037; 3,843,641, etc.
Cephalosporins having an acylureido acyl side chain are disclosed in U.S. Pat. Nos. 3,687,949 and 3,925,368 and German Offenlegungsschrift Nos. 2,513,954 and 2,514,019. Our prior application Ser. No. 671,788, filed Mar. 30, 1976, discloses [[[(2,4-dioxo-1-imidazolidinyl)amino]carbonyl]amino]acetyl cephalosporin derivatives.